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Externally, the rocket is similar to the Long March 2E from which it was derived. Most of the changes involve the addition of redundant systems to improve safety, although there are some structural modifications that allow the rocket to support the heavier fairing required by the Shenzhou capsule. The rocket is also capable of lifting heavier payloads with the addition of extra boosters to the first stage.[6]

The rocket also has an "advanced fault monitoring and diagnosis system to help the astronauts escape in time of emergency" (in other words, a launch escape system), and is the first Chinese made rocket to be assembled and rolled out to its launch site vertically.[7]

A derivative called Long March 2F/G, first launched in 2011, was designed to launch space laboratories such as Tiangong-1 and Tiangong-2. It dispenses with the launch escape system and sports a larger fairing to accommodate the bulkier payloads.[8]

During the Shenzhou 5 flight, Yang Liwei became unwell due to heavy vibrations from the rocket. Although the problem was reduced somewhat by modifications to the rocket, vibrations were reported again in Shenzhou 6 necessitating further changes. According to Jing Muchun, chief designer of the Long March 2F "We made changes to the pipelines of the rocket engine, adjusting its frequency. A new design for the pressure accumulator produced evident results. The vibration has now been reduced by more than 50 percent." [9]

^ abJones, Morris (2016-01-27). "Last Launch for Long March 2F/G". Space Daily. Retrieved 2016-04-07. The principal difference between the Shenzhou-launching Long March 2F and its 2F/G cousin is easy to spot. The 2F/G carries a very different payload fairing at its top. This accounts. for the larger dimensions of the Tiangong laboratory, which wouldn't fit inside the standard payload fairing for the 2F.
It also lacks an emergency escape system. With no astronauts on board, the escape rocket and stabilizer panels that help Shenzhou spacecraft to separate from their rocket in a launch failure are not needed. This simplifies the design and also reduces the weight of the rocket. That's critical. Tiangong modules weigh more than Shenzhou spacecraft, so this helps to keep the overall launch mass within performance limits.